Sir Alex Ferguson gestures from the Ewood Park sideline but the 0-0 result means time may have run out on Manchester United's Premier League title hopes. Photograph: Nigel Roddis/Reuters

Sir Alex Ferguson may not quite have waved a white flag and surrendered to Chelsea but the Manchester United manager did acknowledge that the Premier League title is sliding from his team's grasp.

United's disappointing 0-0 draw at Ewood Park yesterday handed the initiative to Carlo Ancelotti's side and, four days after the frustration of a Champions League exit to Bayern Munich, Ferguson could not disguise his disappointment.

"The title is slipping away when you don't get a result in a game like today," said the United manager, who is now dependent on his rivals faltering. "We are now a point behind Chelsea and they have a game in hand which would take it to four points. It's a big gap.

"I think it has slipped away from us today. It's going to be difficult to win this league but we have a lifeline if Chelsea blow it."

Lacking the injured Wayne Rooney, United struggled in the face of some obdurate Blackburn defending with Rooney's replacement, the deep-lying Dimitar Berbatov, cutting an increasingly frustrated figure. "We created plenty of chances and had enough opportunities to take them," said Ferguson, whose gamble in selecting Federico Macheda in attack failed.

"The pitch wasn't great but we should have done better in this game. It was a disappointing result – it's a blow, there is no doubt about that. This is a fantastic result for Chelsea."

Whether Ancelotti's men maintain their advantage depends on the events of tomorrow night. "They have a home game against Bolton on Tuesday which they will be fancied to win, of course; to my mind they have an easy game," said Ferguson who, having used all his substitutes, was forced to leave the injured Rio Ferdinand to play out the last 10 minutes as a virtual passenger. The England captain picked up a groin strain on a day when Ryan Giggs collected a hamstring injury and John O'Shea also received a knock.

Ferguson was hopeful they would recover in time for Saturday's Manchester derby. Their manager hopes they will recover in time for a meeting with United's "noisy" neighbours. "We have a derby game against Manchester City next week," he said. "It's a derby game that takes away the business of chasing the league. It is a different kind of game. It will be entertaining in terms of the pride of the supporters."

Safe from relegation worries but out of European contention, Allardyce's team were playing for pride yesterday. Not to mention honour. The Blackburn manager, a good friend of Ferguson who enjoyed a day out at Aintree races with him last week, had been affronted by pre-match suggestions that, after holding Chelsea to a recent draw at Ewood Park, he might quietly allow his players to concede this game.

"We've left Manchester United in a difficult position, I think we've done a good bit of damage to United's title aspirations," he said. "The position at the top of the table has changed 20 times this season but Sir Alex knows he's got to win every game now and hope Chelsea slip up. I wouldn't say it's all over but it's going to be difficult for them. Everyone thought Chelsea were out of it but they've fought back."

Allardyce, who lost his key defender Chris Samba to injury in the first half and saw Samba's partner Phil Jones, an 18-year-old novice centre-half, win the man-of-the-match award, was not surprised his impressive goalkeeper, Paul Robinson, had relatively few important saves to make.

"Teams can't expect to come to Ewood Park now and create a lot of chances," he said. "And United are not as potent without Wayne Rooney. The stats tell you that. Their second top scorer after Rooney is OG [own goals], all their other players are in single figures. It's very unlike Man United. The creativity is still there but perhaps their finishing is not quite so good this year – you would have expected them to score from the chances they had."

It will be scant consolation to Ferguson that he is not the first manager to have come away from Ewood cursing this season. Blackburn have lost only twice – to Manchester City and Tottenham Hotspur – at home in the league this season. "We've now drawn with Liverpool, Chelsea and United here, defensively we were outstanding today," said Allardyce, whose side host Arsenal on 1 May. "Teams can't expect to come to Ewood and have it easy."